Speed-changer.



I \M. 3. MW.

' w. T. SEARS.

SPEED CHANGER. APPLIOATION FILED SEPT. 29, 1906.

PATBNTBD MAR ZO 1906.

2 sums-sushi. 2.

Witneses: I Ihv i toz" I & %\\W' I,

. Attorney 45' adapted by the turning of that shaft to ac- 1 UNITED STA ES PATENT OFFICE.

. WILLARD THOMAS SEARS, or PHILADELPHIA, PENNSYLVANIA, ASSIGNOR To all whom it may concern:

TO NILES-BEMENT-POND COMPANY; OF JERSEY CITY, NEW JERSEY.

' sP ED-cHANeEn.

Specification of Letters Patent.

,Patirted March 1906.

Application filed September 29, 1905- Serial No. 280,587-

Be'it known that .I, WILLARD THOMAS SEARS, a citizen of the ing in Philadelphia, Philadelphia county, Pennsylvania, (post-office address, Twentyfirst and Callowhill streets, Philadelphia, Pennsylvania,) have invented certain new and useful Improvements in Speed-Changers, of which the following is a specification.

This invention, pertaining to speed-changers, will be readilyunderstood from the -fo I lowing description, taken in connection with the accompanying drawings, in .which' Figure 1 is a front elevation of a speedchanging mechanism exemplifying my invention; Fig. 2, a perspective'view of the gear-throwing cam,with its lobe )17 in re treated position, Fig; 3, a diametrical section 'of the samecam with itslob'e 19 in retreated position; Fig. 4, a front elevation of parts "generally similar to those illustrated in the preceding'figures, but'illustrating the employment, of toothed clutches instead of slidmg gears; and Fi 5, a similar view of parts,

illustrating a mo ification in which the elastic element of the system is disposed in the splined on the drivingeshaft and adapted to engage gear 6, the two gears 7 and 8 being unified so as to slide together and their combined thickness being less than the distance between the gears 5 and 6;, 9, a lever-shifter for sliding the gears 7 and 8 10, a levershifter for throwing the friction-clutch into and out of action; 11, anadjusting-shaft;

7 friction clutch'; 13,agearthrowing cam,con-- sid'ered as a whole, mounted on 'theadjust- 5o cumferential 12,"a cam fast on the adjusting-shaft and tuate the lever 10 to engage or discngage'the ing-shaft so as to be rotated by it; 14, a cirengaging "the ever 9 and'being of such form that the turning of the adjusting-shaft may bring about theshifting of gears 7 and 8 5 15,

United States, resid groove in cam 13, this groove a flange at one end of cam 13, capable of slid.- 5 5 ing away from the end of the cam; 16, a tongue. projecting inwardly from this flange and forming a portion of cam 13 and turning with it; 17, theinner extremity of this tongue,

forming one of the lobes of cam 13; 18, a

flange at the opposite end of cam 13; 19, the inner extremity of a tongue projecting inwardly from'flange 18 and forming 'a second lobe in the groove of cam 13 20, a spring urging'flange '18' toward the gear-throwing cam; 21, a spring urgin flange 15 toward the cam, and 22 the genera bod of cam 13.

Assume cam 13 to be a so id camthat is to say, a cam whose groove has separable Wallsand assume the parts to be in the position indicated in Fig. 1, with all parts at rest. It will be observed that gears 7 and 8 are in neutral shaft '2 be rotated no motion ed to the driven shaft. shaft 11 be appropriately turned ,lobe 17 will will be impart- I cause lever 9 to shift gears 7 and 8 till gear 7 engages gear 5, cam 12 then throwing the friction-clutch intqaction, whereupon the driving-shaft will r tate andtransmit .mo-

tion to the driven'sh t at relative rate due to the proportioning of gears 7 and 5. If

the adjusting-shaft be turned somewhat farther, it will manifestly bring about the release of the friction-clutch and the subse- I quent restoration of the driving-gears to the neutral position, and if the adjusting-shaft be turned still farther lobe 19 will comeinto action and cause the transmission to take effeet while gears 8 and 6 are engaged. Let it go be assumed that when the attempt is'made to slide gear 7 into engagement with gear 5; the teeth and spaces are not opposite, the result being that the ends of the teeth of one gear strike the ends of the teeth of the other 5 gear. If cam 13 has its groove provided with stable walls, then this clashing of the gear-teeth would obviously preventthe further turning of the cam; but in the present case when the clash occurs lobe. 17 yields outwardly against the resistance of spring 21, and .when the friction-clutch is thrown into engagement and the driving-shaft starts into motion the clashing gear-teeth will quickly reach permissive position, whereupon the 'reaction'of spring 21' will restore lobe 1 7 to its normal position in the cam and complete the engagement of the gears. Similarly position, so that if driving- If now adjusting- 75 cam 13 instead of having yielding lobes is a teeth calls for such yielding,

present.

. roviding for two more changes of speed.

when the adjusting-shaft is turned to bring l lobe 19 into action.

Cam 13, considered as a Whole, has a nor- 1 mal longitudinal position, and thepurpose of the springs isto virtually permit the cam to yield longitudinallywhen the clashing of gearand to restore the cam to normal position when the teeth properly engage. Instead of permitting the cam-as a whole'toyield in case the gear-teeth clash it is manifestly sufficient that the active lobes of the 'cam' be arranged to yield when necessary.

It will be manifest that the system is applicable to toothed clutches as well as to Slldmg gears. A modification, illustration, and arrangement employing toothed clutches is illustrated in Fig. 4, in which gears 23 and 24, each provided with toothed clutchfaces, are loose on shaft 2, these gears being alternatively locked to' the shaft by means of toothed clutch 25, splined to the shaft and shifted from the neutral to either active position by the action of the cam in the same manner as has been described in connection with the sliding gears. If in sliding the clutch the ends of the tooth make clashing contact, the active cam lobe will yield against the resistance of itsspring, and the proper engagement of the clutches will occur when the conditions are favorable. Again,

the yieldi'n of the shifting mechanism in case of un avorable conditions presenting themselves may be arranged to occur not at the lobe of the cam, but at a point in the shifting mechanism beyond the lobe. Fig. 5 illustrates such a modification, in which the rigidly-formed structure, and the yielding element is found in the spring 26 between the shiftin -levers 25. The action will be obvious. 11 any event whether the shifted member be a toothed clutch or a sliding gear and whether the yielding device be embodied in the cam or elsewhere it is often highly desirable that notwithstanding the action may be elastic or yielding when throwing the device into action a positive throwout be For instance, assume that the gearing (illustrated in Fig. 1) providing for two changes of speed, be employed in conjunction with'a second similar arrangement f one pair of gears be thrown into action by means of an elastic shifting device and a previously-used pair of gears be thrown out of action by means of an elastic shifting device, it might ha pen that the last-mentioned device wou d not perform promptly, in which event gears corresponding with two different speeds might be in engagement at once, the result of which contingency would be a deadlock and probably a breakage. While the positive throw-out might not be essential in all cases, it is to be observed that member, a cam, means for turning the cam, a

lever connecting the cam and sliding member whereby the turning of the cam shifts the sliding member, and a sprin coacting with the cam and lever to permit t e sliding member to rest while the cam is turning and tend-' ing to move the sliding member to position of en agement with the. first toothed member.

2. In a speed-changer, the combination, substantially as set forth, of a first toothed member, a shaft, a slidin toothed member mounted on the shaft an adapted to move to and from engagement with the first toothed member, a cam, means for turning the cam, a lever connecting the cam and sliding member whereby the turning of the cam shifts the sliding member, a spring coacting with the cam and lever to permit the sliding member to rest while the cam is turning and tending to move the sliding member to active position, and a cam' member upon said cam arranged to operate upon said lever independent of the action of the spring, whereby the turning of the cam results in the positive throwing of the sliding member out of engagement with the first toothed member.

3. In a speed-changer, the combination, substantially as set forth, of a shaft, a sliding toothed member, a shifter for moving the sliding toothed member, a lobed cam for o erating the shifter, means for movin tie cam, and springs enga ing the cam and 101ding its lobes in normal position and adapted to yield and permit the retreat of the lobes.

4. In a speed-changer, the combination, substantially as set forth, of a shaft, a sliding toothed member, a shifter for moving the sliding toothed member, a lobed cam for o crating the shifter, means for movin t e cam, springs enga ing the cam and ho ding its lobes in normal position and adapted to yield and permit the retreat of the lobes, a friction-clutch upon the shaft, a shifter for actuating the clutch, a cam for operating the shifter of the clutch, and means connecting said two cams to cause them to move in unison.

5. In a speed-changer, the combination, substantially as set forth, of a shaft, a sliding toothed member, a shifter for moving the sliding toothed member, a lobed cam for operating the shifter, means for movin cam, and springs holding the cam obes yieldingly to normal position.

the

' 6. a speed-changer, the combination,

substantially as setforth, of a shaft, a sliding toothed member, a shifter for moving the sliding toothed member, a lobed cam for op- 5 crating the shifter, a rotary adjusting-shaft carryingsaid cam, and s rin s on agin said camand serving to yiel' ing y ho (1 its obes to ngrmal'position.

7. In a speed hanger, the combination, substantiallyas set forth, of a driving-shaft, a sliding toothed member, a shifter'for moving the sliding toothed member, a lobed cam for operating the shifter, a rotary adjusting 15 said cam and serving to yieldinglyh lobes to normal positlon, a friction-clutch on the driving-shaft, a shifter for the clutch, and

usting-shaft for operating a cam on said ad said clutch-shifter.-

I substantially as set forth, of a shaft, a toothed sliding member, a shifter for movingthe slid cam-body shaft carrying saidcam, springs engaging.

'8. In a speed-changer, the combination,

tion.

ng in said cam-body. andof said groove, and springs holding said shaft, acircumferentially-grooved cam-b0 y on said adj usting-shaft, ton ues sliding in said and carrying 10 es forming portions oft e Walls of said groove, springs holding said tongues yieldingly to normal 'posi tion, a friction-clutch on the driving-shaft, a

shifter for the clutch, and-a cam on said ad-' 'justin '-shaft for operating the clutch-shifter. its a 4 10. n a speed-chan er, the combination,

substantially as set fort ofa slidin toothed member, a shifting device for shi ting said member positivel V in one direction, and a.

sprling in the shi ting device for elastically s ting said member in the opposite direc- WILLARD THOMAS SEARS.

Witnesses:

E. H. WRAY, AnonmAL'n M. OBRIEN. 

